This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-258911 filed Aug. 29, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a wiring board with a signal transmission circuit, which transmits a signal at high speed, and to electronic equipment using the wiring board.
2. Description of the Related Art
Electronic equipment used in the field of information technology, such as computers, may require a function to transmit a signal at high speed from a signal source comprising a DSP (Digital Signal Processor) or an MPU (Micro Processing Unit) to a memory element or from a memory element to an MPU or a logic LSI.
In the case where a signal transmission circuit for high-speed signal transmission is formed on a wiring board, a laminated board, for example, including a plurality of conductive layers made of copper and one or a plurality of insulating layers made of epoxy resin, is used as the wiring board.
In recent years, as the driving speed of the signal source is increased, the frequency of a signal transmitted on the wiring board of electronic equipment is also increased. Meanwhile, since the size of electronic equipment itself is reduced with each passing year, a wiring board in which the signal transmission circuit is designed as a distributed constant circuit has been required.
Further, due to the factors of the increase in frequency and the reduction in size, the quality of a signal on the electric circuit has been required to be high. For this purpose, to eliminate an influence of a reflection wave due to a characteristic impedance mismatch, the need for matching of characteristic impedances on wires or members on the board has been increased.
To solve the above problem, a major object of the present invention is to provide a wiring board that can easily realize impedance matching in a distributed constant circuit, and electronic equipment, such as a computer, using the wiring board.
According to an embodiment of the present invention, there is provided a wiring board comprising a signal transmission circuit designed as a distributed constant circuit, the signal transmission circuit including:
a first transmission line connecting a first electric component and a second electric component; and
a second transmission line connecting the second electric component to a terminator resistor of the distributed constant circuit,
at least the first transmission line including a plurality of signal lines arranged in parallel, which transmit an equivalent signal in parallel substantially.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.